Autopiquer - a robust and reliable peak detection algorithm for mass spectrometry

We present a simple algorithm for robust and unsupervised peak detection by determining a noise threshold in isotopically resolved mass spectrometry data. Solving this problem will greatly reduce the subjective and time consuming manual picking of mass spectral peaks and so will prove beneficial in many research applications. The Autopiquer approach uses autocorrelation to test for the presence of (isotopic) structure in overlapping windows across the spectrum. Within each window, a noise threshold is optimized to remove the most unstructured data whilst keeping as much of the (isotopic) structure as possible. This algorithm has been successfully demonstrated for both peak detection and spectral compression on data from many different classes of mass spectrometer and for different sample types and this approach should also be extendible to other types of data that contain regularly spaced discrete peaks

Physical Dating Aggression Growth During Adolescence

The development of Physical Dating Aggression from the age of 16 to 18 years was investigated in relation to time-invariant predictors (gender, parental education, family composition, number of partners) and to time-varying effects of delinquent behavior and perception of victimization by the partner. The sample consisted of 181 adolescents with a current or past dating relationship. Results showed an average trend of decrease from 16 to 18 years with significant inter-individual variability in intra-individual change across time, suggesting that different trajectories of Physical Dating Aggression among the population can be found. Inter-individual variability can be explained by background variables representing a distal risk on Dating Aggression at 16 years (mother's education, precocious dating experience), and by time-varying effect of delinquent behavior and perception of partner perpetration. These latter variables can act as snares (Moffitt 1993), representing mechanisms responsible for prolonging the otherwise normative pattern of decrease of Physical Dating Aggression

Juvenile Offenders’ Alcohol and Marijuana Trajectories: Risk and Protective Factor Effects in the Context of Time in a Supervised Facility

The current study modeled trajectories of substance use from ages 15 to 20 among 1,095 male serious juvenile offenders (M age = 16.54; 42% African-American, 34% Latino, 20% European-American, and 4% other ethnic/racial backgrounds) and prospectively predicted trajectories from risk and protective factors before and after controlling for time spent in a supervised setting. Results indicated that supervised time suppressed age-related growth in substance use. Trajectories of offenders with no supervised time and low levels of supervised time increased in substance use across age, whereas offenders with high levels of supervised time showed no growth. Almost all risk and protective factors had effects on initial substance use but only adolescent history of substance use, impulse control, and psychosocial maturity had an effect on change in substance use over time. Findings highlight the importance of formal sanctions and interventions superimposed on normal developmental processes in understanding trajectories of substance use among serious juvenile offenders